Synthesis of symmetrical and unsymmetrical triarylpyrylium ions via an inverse electron demand Diels–Alder reaction

Abstract

One-pot, scalable synthesis of symmetrical and unsymmetrical 2,4,6-triarylpyrylium ions via a highly regioselective inverse electron demand Diels–Alder (IEDDA) reaction.

IndiFluors: A New Full-Visible Color-Tunable Donor–Acceptor–Donor (D1–A–D2) Fluorophore Family for Ratiometric pH Imaging during Mitophagy

“…26 Recently, Fathimath Salfeena et al reported the synthesis of an unsymmetrical triarylpyrylium ion through the inverse electron demand Diels−Alder (IEDDA) reaction with moderate yields. 27 However, the lack of bridging between donors and acceptors and additional γ-substituted aryl motifs cause a nonradiative transition. To overcome these limitations, we synthesized a pentacyclic pyrylium (PY) fluorophore with bridging cyclohexyl rings using a diverse range of catalysts, and perchloric acid (70%) was found to be the most promising catalyst among 16 catalysts considering the reaction time, purification, and the product yields (Table 1).…”

“…The γ-substituted triarylpyrylium derivative using acetophenone and dypnone was also reported to be in very low yields . Recently, Fathimath Salfeena et al reported the synthesis of an unsymmetrical triarylpyrylium ion through the inverse electron demand Diels–Alder (IEDDA) reaction with moderate yields . However, the lack of bridging between donors and acceptors and additional γ-substituted aryl motifs cause a nonradiative transition.…”

Closer Look at Inverse Electron Demand Diels–Alder and Nucleophilic Addition Reactions on s-Tetrazines Using Enhanced Sampling Methods

“…Hence it has been proved by several calculations [10][11][12] and experiments [13,14] that BF 3 is a highly efficient catalyst for the iEDDA reactions [1]. At the same time, based on experimental results reported in the previous study, the reaction could produce the product with up to 82% yield in the presence of BF 3 [4].…”

A Strategy To Obtain o-Naphthoquinone Methides: Ag(I)-Catalyzed Cyclization of Enynones for the Synthesis of Benzo[h]chromanes and Naphthopyryliums

“…In 2017, You reported an elegant C–H activation/annulation reaction for the one-pot synthesis of fused pyrylium cations . Recently, Sasidhar demonstrated the synthesis of triarylpyrylium via an inverse-electron-demand Diels–Alder reaction . Although great progress has been achieved, the rapid assembly of pyryliums with tunable substituents still would be advantageous.…”